dos-vga-arena-shooter-game/game.c

#include <stdio.h>
#include <math.h>
#include <conio.h>
#include <stdlib.h>
#include <time.h>

#include "sprites.h"
#include "system/vga.h"
#include "system/keyboard.h"
#include "system/mouse_io.h"
#include "system/pc_stuff.h"

#include "bmpload.h"
#include "const.h"
#include "arena.h"
#include "movement.h"

struct BMPImage spritesheetImage;
struct VGAColor vgaColors[256];

struct CompiledSpriteRender rabbit, mouse, bullet, enemy;
struct RabbitPosition rabbitPosition = {
  .rabbitPosition = { 60, 60 },
  .rabbitLimits = { { 20, 20 }, { 180, 180 } },
  .mousePosition = { 0, 0 },
  .rabbitVelocity = { 0, 0 },
  .mouseDotPosition = { 0, 0 }
};

struct EnemyPosition enemyPosition[ENEMY_MAX_COUNT];

struct BulletPosition rabbitBulletPosition[RABBIT_BULLET_LIMIT];
struct RabbitWeaponry rabbitWeaponry;

void setupRabbitBullets() {
  int i;

  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
    rabbitBulletPosition[i].isActive = 0;
    rabbitBulletPosition[i].willBeInactive = 0;
  }

  rabbitWeaponry.cooldown = 0;
}

void setupEnemies() {
  int i;

  for (i = 0; i < ENEMY_MAX_COUNT; ++i) {
    enemyPosition[i].isActive = 0;
    enemyPosition[i].willBeInactive = 0;
  }
}

void attemptToFireRabbitBullet() {
  char okToFire = 0, availableBullet, i;
  signed char doubleVelocityX, doubleVelocityY;

  if (rabbitWeaponry.cooldown > 0) return;

  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
    if (rabbitBulletPosition[i].isActive == 0) {
      okToFire = 1;
      availableBullet = i;
      break;
    }
  }

  if (!okToFire) return;

  rabbitWeaponry.cooldown = RABBIT_BULLET_COOLDOWN;

  doubleVelocityX = sin(rabbitPosition.mouseAngle * DEG2RAD) * (RABBIT_BULLET_VELOCITY * 2);
  doubleVelocityY = -cos(rabbitPosition.mouseAngle * DEG2RAD) * (RABBIT_BULLET_VELOCITY * 2);

  rabbitBulletPosition[availableBullet].isActive = 1;
  rabbitBulletPosition[availableBullet].willBeInactive = 0;
  rabbitBulletPosition[availableBullet].x = rabbitPosition.rabbitPosition[0];
  rabbitBulletPosition[availableBullet].y = rabbitPosition.rabbitPosition[1] - RABBIT_BULLET_HEIGHT_START;
  rabbitBulletPosition[availableBullet].oldX = rabbitBulletPosition[availableBullet].x;
  rabbitBulletPosition[availableBullet].oldY = rabbitBulletPosition[availableBullet].y;

  rabbitBulletPosition[availableBullet].velocityXSteps[0] = doubleVelocityX / RABBIT_BULLET_VELOCITY;
  rabbitBulletPosition[availableBullet].velocityXSteps[1] = doubleVelocityX % RABBIT_BULLET_VELOCITY;

  rabbitBulletPosition[availableBullet].velocityYSteps[0] = doubleVelocityY / RABBIT_BULLET_VELOCITY;
  rabbitBulletPosition[availableBullet].velocityYSteps[1] = doubleVelocityY % RABBIT_BULLET_VELOCITY;

  rabbitBulletPosition[availableBullet].velocityStep = 0;
}

void advanceRabbitBullets() {
  char i;
  signed char velocityX, velocityY;

  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
    if (!rabbitBulletPosition[i].isActive) continue;

    rabbitBulletPosition[i].oldX = rabbitBulletPosition[i].x;
    rabbitBulletPosition[i].oldY = rabbitBulletPosition[i].y;

    rabbitBulletPosition[i].x += rabbitBulletPosition[i].velocityXSteps[rabbitBulletPosition[i].velocityStep];
    rabbitBulletPosition[i].y += rabbitBulletPosition[i].velocityYSteps[rabbitBulletPosition[i].velocityStep];

    if (rabbitBulletPosition[i].x < MOUSE_LIMIT_LEFT) rabbitBulletPosition[i].willBeInactive = 1;
    if (rabbitBulletPosition[i].x >= MOUSE_LIMIT_RIGHT) rabbitBulletPosition[i].willBeInactive = 1;
    if (rabbitBulletPosition[i].y < MOUSE_LIMIT_TOP) rabbitBulletPosition[i].willBeInactive = 1;
    if (rabbitBulletPosition[i].y >= MOUSE_LIMIT_BOTTOM) rabbitBulletPosition[i].willBeInactive = 1;

    rabbitBulletPosition[i].velocityStep = 1 - rabbitBulletPosition[i].velocityStep;
  }

  if (rabbitWeaponry.cooldown > 0) rabbitWeaponry.cooldown--;
}

void detectPlayerBulletToEnemyCollisions() {
  int bulletIdx, enemyIdx;

  for (bulletIdx = 0; bulletIdx < RABBIT_BULLET_LIMIT; ++bulletIdx) {
    if (!rabbitBulletPosition[bulletIdx].isActive) continue;

    for (enemyIdx = 0; enemyIdx < ENEMY_MAX_COUNT; ++enemyIdx) {
      if (!enemyPosition[enemyIdx].isActive) continue;

      // bullets hit enemies if:
      // * bulletY - bullet_height_start is within 3px of enemy base
      // * 
    }
  }
}

struct SpawnPointRange {
  int left, width;
  int top, height;
};

struct SpawnPointRange spawnPointRanges[1] = {
   { .left = 50, .width = 30, .top = 50, .height = 30 }
};

void maybeSpawnEnemy() {
  char canSpawn;
  int i, availableEnemy;
  int spawnX, spawnY;

  for (i = 0; i < ENEMY_MAX_COUNT; ++i) {
    if (!enemyPosition[i].isActive) {
      availableEnemy = i;
      canSpawn = 1;
      break;
    }
  }

  if (!canSpawn) return;

  spawnX = spawnPointRanges[0].left + rand() % spawnPointRanges[0].width;
  spawnY = spawnPointRanges[0].top + rand() % spawnPointRanges[0].height;

  enemyPosition[availableEnemy].isActive = 1;
  enemyPosition[availableEnemy].enemyPosition[0] = spawnX;
  enemyPosition[availableEnemy].enemyPosition[1] = spawnY;
}

void setupEnemySprites() {
  buildCompiledSprite(
    &sprite_enemy,
    &enemy,
    SPRITE_ENEMY_WIDTH,
    SPRITE_ENEMY_HEIGHT,
    SPRITE_ENEMY_OFFSET_X,
    SPRITE_ENEMY_OFFSET_Y
  );
}

void setupRabbitSprites() {
  buildCompiledSprite(
    &sprite_rabbit,
    &rabbit,
    SPRITE_RABBIT_WIDTH,
    SPRITE_RABBIT_HEIGHT,
    SPRITE_RABBIT_OFFSET_X,
    SPRITE_RABBIT_OFFSET_Y
  );

  buildCompiledSprite(
    &sprite_mouse,
    &mouse,
    SPRITE_MOUSE_WIDTH,
    SPRITE_MOUSE_HEIGHT,
    SPRITE_MOUSE_OFFSET_X,
    SPRITE_MOUSE_OFFSET_Y
  );

  buildCompiledSprite(
    &sprite_bullet,
    &bullet,
    SPRITE_BULLET_WIDTH,
    SPRITE_BULLET_HEIGHT,
    SPRITE_BULLET_OFFSET_X,
    SPRITE_BULLET_OFFSET_Y
  );
}

struct MouseStatus mouseStatus;

void renderMouse() {
  mouse.x = rabbitPosition.mousePosition[0];
  mouse.y = rabbitPosition.mousePosition[1];

  drawCompiledSprite(&mouse);
  drawPixel(rabbitPosition.mouseDotPosition[0], rabbitPosition.mouseDotPosition[1], 2);
}

void renderRabbit() {
  rabbit.x = rabbitPosition.rabbitPosition[0];
  rabbit.y = rabbitPosition.rabbitPosition[1];

  drawCompiledSprite(&rabbit);
}

void renderEnemies() {
  int i;

  for (i = 0; i < ENEMY_MAX_COUNT; ++i) {
    if (!enemyPosition[i].isActive) continue;

    enemy.x = enemyPosition[i].enemyPosition[0];
    enemy.y = enemyPosition[i].enemyPosition[1];

    drawCompiledSprite(&enemy);
  }
}

void renderRabbitBullets() {
  char i;

  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
    if (!rabbitBulletPosition[i].isActive) continue;

    bullet.x = rabbitBulletPosition[i].x;
    bullet.y = rabbitBulletPosition[i].y;

    drawCompiledSprite(&bullet);
  }
}

struct SpriteBounds bounds;

void drawOnlyMouseArena() {
  mouse.x = rabbitPosition.oldMousePosition[0];
  mouse.y = rabbitPosition.oldMousePosition[1];
  getSpriteBounds(&mouse, &bounds);
  drawOnlyArena(&bounds);

  bounds.top = rabbitPosition.oldMouseDotPosition[1];
  bounds.bottom = rabbitPosition.oldMouseDotPosition[1];
  bounds.left = rabbitPosition.oldMouseDotPosition[0];
  bounds.right = rabbitPosition.oldMouseDotPosition[0];
  drawOnlyArena(&bounds);
}

void drawOnlyRabbitArena() {
  rabbit.x = rabbitPosition.oldRabbitPosition[0];
  rabbit.y = rabbitPosition.oldRabbitPosition[1];
  getSpriteBounds(&rabbit, &bounds);
  drawOnlyArena(&bounds);
}

void drawOnlyEnemiesArena() {
  int i;

  for (i = 0; i < ENEMY_MAX_COUNT; ++i) {
    if (!enemyPosition[i].isActive) continue;

    enemy.x = enemyPosition[i].oldEnemyPosition[0];
    enemy.y = enemyPosition[i].oldEnemyPosition[1];
    getSpriteBounds(&enemy, &bounds);
    drawOnlyArena(&bounds);

    if (enemyPosition[i].willBeInactive) {
      enemyPosition[i].willBeInactive = 0;
    }
  }
}

void drawOnlyRabbitBulletArena() {
  int i;
  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
    if (!rabbitBulletPosition[i].isActive) continue;

    bullet.x = rabbitBulletPosition[i].oldX;
    bullet.y = rabbitBulletPosition[i].oldY;
    getSpriteBounds(&bullet, &bounds);
    drawOnlyArena(&bounds);

    if (rabbitBulletPosition[i].willBeInactive) {
      rabbitBulletPosition[i].isActive = 0;
    }
  }
}

int setupGame() {
  FILE *fh;

  installKeyboardHandler();
  initializeDrawBuffer();

  fh = fopen("sprtsht.bmp", "rb");
  if (readBMPIntoNewMemory(fh, &spritesheetImage)) return 1;
  fclose(fh);

  spritesheetImage.transparentColor = 0;

  setupWallSprites(&spritesheetImage);
  setupRabbitSprites();
  setupRabbitBullets();
  setupEnemySprites();

  setVideoMode(VIDEO_MODE_VGA_256);
  bmp256ColorPaletteToVGAColorPalette(&spritesheetImage, vgaColors);
  setVGAColors(vgaColors, 256);

  activateMouse(&mouseStatus);

  buildArena();
  clearArenaRedrawRequests();

  srand(time(NULL));

  return 0;
}

double speedCalcs[200];
int currentSpeedCalc = 0;
double averageSpeedCalc;
clock_t startTime;

// non cdecl is put params into eax, ebx, and ecx

int main(void) {
  byte *drawBuffer;
  int keepRunning = 1;

  void (*code)(byte *);

  if (setupGame()) return 1;

  drawBuffer = getDrawBuffer();

  maybeSpawnEnemy();

  while (keepRunning) {
    readMouse(&mouseStatus);
    populateKeyboardKeydownState();
    handleRabbitMovement(
      &rabbitPosition,
      &keyboardKeydownState
    );
    captureAndLimitMousePosition(
      &rabbitPosition,
      &mouseStatus
    );
    calculateTargetAngle(
      &rabbitPosition,
      &mouseStatus
    );

    if (mouseStatus.leftButtonDown) attemptToFireRabbitBullet();

    advanceRabbitBullets();

    drawOnlyRabbitArena();
    drawOnlyEnemiesArena();
    drawOnlyMouseArena();
    drawOnlyRabbitBulletArena();

    redrawArena();

    renderRabbit();
    renderEnemies();
    renderMouse();
    renderRabbitBullets();

    waitStartVbl();

    copyDrawBufferToDisplay();

    waitEndVbl();

    if (keyboardKeydownState.KEY_ESC) { keepRunning = 0; }
  }

  freeBMP(&spritesheetImage);

  setVideoMode(VIDEO_MODE_80x25_TEXT);
  uninstallKeyboardHandler();

  averageSpeedCalc = 0;
  for (currentSpeedCalc = 0; currentSpeedCalc < 200; ++currentSpeedCalc) {
    averageSpeedCalc += speedCalcs[currentSpeedCalc];
  }

  averageSpeedCalc /= 200;

  fprintf(stderr, "average: %f\n", averageSpeedCalc);

  return 0;
}